EU to Britain: No access to single market without migration

European Union leaders spelled out stark conditions for a new relationship with a departing Britain on Wednesday, warning that if British business wants to keep access to Europe's single market, the country must accept European workers, too.

The leaders produced no clear rehaul for their shaken union after an unusual and emotionally charged summit, but agreed they must make it more relevant to citizens and keep it from disintegrating after Britain's unprecedented vote to leave. The 27 remaining presidents, chancellors and prime ministers said they're "absolutely determined to remain united," EU Council President Donald Tusk said.

They met without British Prime Minister David Cameron, who left Brussels on Tuesday night without any clear divorce plan, fending off pressure for a quick exit and punting the complex departure negotiations to his successor. In Britain, nominations opened Wednesday for a new Conservative leader to replace him after his devastating political miscalculation in calling last week's referendum.

Other EU leaders warned the U.K. that if it wants to continue to enjoy the seamless single market after its departure, it would also have to accept that EU citizens can continue to enter Britain. That's the crux of the current tensions: Britain's "leave" vote hinged on concerns about migration from poorer EU countries.

The leaders emerged insisting that the "four freedoms" central to European unity are indivisible: the free movement of people, services, goods and finances.

They were focusing Wednesday on how to deal with the rest of the continent now that Britain is leaving. There's a widespread sense that the post-war project to foster peace via trade has become a bureaucratic, undemocratic behemoth with little meaning for its 500 million citizens. The initial EU founding nations in the west lean toward a tighter, closer union.